33220991 has 4 divisors (see below), whose sum is σ = 33233184. Its totient is φ = 33208800.

The previous prime is 33220981. The next prime is 33221003. The reversal of 33220991 is 19902233.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-33220991 is a prime.

It is a super-2 number, since 2×33220991² = 2207268486044162, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (33220981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71 + ... + 8151.

It is an arithmetic number, because the mean of its divisors is an integer number (8308296).

Almost surely, 2^33220991 is an apocalyptic number.

33220991 is a deficient number, since it is larger than the sum of its proper divisors (12193).

33220991 is an equidigital number, since it uses as much as digits as its factorization.

33220991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12192.

The product of its (nonzero) digits is 2916, while the sum is 29.

The square root of 33220991 is about 5763.7653491446. The cubic root of 33220991 is about 321.4678368305.

The spelling of 33220991 in words is "thirty-three million, two hundred twenty thousand, nine hundred ninety-one".